I’d agree that Google Chrome was noticeably faster than Firefox up until around a decade ago. However, I haven’t noticed it to be any faster since then. What makes web browsing faster for me is the use of web extensions that disable the downloading of unnecessary resources and/or the execution of pointless Javascript, e.g., NoScript, uMatrix, uBlock, Privacy Badger, etc – the same extensions that will have their abilities greatly reduced by Manifest v3.